The progress of the semiconductor industry in recent years has brought a high computing power to end users using various types of end terminals such as Personal Computes (PCs). PCs today are equipped with powerful three-dimensional (3D) graphic accelerators capable of rendering hundreds of thousand polygons in a fraction of a second, enabling real time 3D animation of complex scenes.
Despite clear advantages provided by current 3D graphics and animation software and hardware tools, such as high resolution power and a profound user experience when creating graphics and animation files, the graphic content, as currently presented in Internet browsers, is almost exclusively based on two-dimensional types of media (text, graphic-files, movies, Flash animation, etc).
The existing 3D authoring graphics tools create very rich and complex animation content and even present it on their own graphic window, in a real-time frame rate. However, transferring this content, through the Internet or any other communication network, is highly limited by the current available technology.
The available 3D internet formats (such as VRML and its successor X3D), based on current technology, are based on polygonal representation, characterized by large volume even for relatively simple geometric objects. The animation supported by these formats is limited to rigid body animation and cannot cope with today's rich animation standards, which present soft, amorphous and dynamically changing geometrical objects.
Current 3D web visualization plug-ins are based on polygonal formats. That is, besides a limited set of primitive objects such as Box, Cylinder, Sphere and Cone, most object geometries are approximated by meshes of polygons. The advantage of this format is that it is most suitable for display on graphical hardware and hence the required computation is minimal and the implementation is usually straightforward. There are, however, a few disadvantages associated with polygonal formats:
A first disadvantage is that typically, the communication network's bandwidth requirements are high, even for simple graphic models. Therefore, the transmission time to the client is high.
Various compression and streaming technologies provide only a partial solution such as the polygonal formats, which are limited to animation of fixed geometries, and do not allow animation of geometries that change with time, such as animated characters, faces, and soft deformable objects.